DE2856242C3 - Check valve that can be unlocked easily - Google Patents

Description

The invention relates to a non-return valve that can be released easily with the features of the preamble of claim 1.

Such check valves sr.A are known in a variety of designs in hydraulics. They are generally used where t. Light loads or other external forces act on a piston-cylinder unit and a hermetically sealed seal is required for retention purposes. When extending against the load, the closing body is lifted hydraulically from its seat by applying pressure directly. Retraction can only take place if the release piston is subjected to a control pressure that is sufficient to open the control pressure is either switched on and off via a special valve in a control line or it is switched on and off via a control line from the opposite working space of the piston-cylinder unit fed. (Ebertshäuser, Components of the oil hydraulics, Part II, page 135 ff, Krauskopf-Verlag 1974, DE-OS 27 16 262.) Such circuits are not possible if the piston-cylinder unit, called cylinder for short, only by a so-called One pipe connection is supplied. One-pipe connections are often used when long pipelines are involved or when assembly is intended to be simplified. In special cases, e.g. B. with smaller farm tractors (z. B. DE-PS 21 29 862), there is also only one single-pipe connection available, which is preceded by a manually operated directional control valve provided with leakage gaps. Another area of application would be the operation of large windows or greenhouse roofs (e.g. DE-PS 15 59 728). Here, too, switching is carried out via piston slide valves.

The invention is therefore based on the object of providing easily releasable check valves of the in question standing type in such a way that a hermetic Ab is reached and - even without a special control line having to be laid - for an output and Retraction by switching a directional valve of the piston slide type is possible Control pressure should already be sufficient so that other consumers can be pressurized when the check valve is unlocked. the The solution should be simple and cheap, have small dimensions and otherwise no additional devices

ίο need.

This object is achieved according to the invention by the features of the characterizing part of the Claim 1. Interchangeable locking devices are, for example, at Ballpoint pens known and already been used in hydraulic valves (DE-AS 11 40 038). However, the valve shown there is operated manually and only serves as an open-close valve through which a flow can flow from one side The solution to the problem according to the invention could

μ should therefore not be suggested.

The invention is explained in more detail using an exemplary embodiment shown in the figures

F i g. 1 shows an easily unlockable check valve in section in its first switching position;

Fig.2 shows a development of part of the Shell of the unlocking piston with a groove system for an interchangeable locking device;

Fig.3 represents the check valve in the second Switching position.

In a housing 1 in a cylindrical bore 2 is a sleeve 3 through a spacer 4 and a Stopper 5 held on one side and another stopper 6 on the other side. The rifle 3 and the spacer 4 have a central cylindrical Hole 7, which is used to guide an unlocking piston 8 serves

This unlocking piston 8 is loaded by a return spring 9, which is supported on the stopper 6 and on a shoulder 11 provided with a seal 10 acts on the shoulder 11 closes an annular groove 12, which merges into a shoulder 14 via a cone 13. A section 15 is attached to the shoulder 14 on, which is provided on its jacket with a coherent groove system 16, which is shown in FIG. 2 over a division is shown as a development, on an enlarged scale. The groove system 16 has around Straight guides 17, 18, 19 and 20, each offset by a rotary partial step, which are guided by inclined guides 21, 22, 23 and 24 are connected to each other. In the groove system

so 16 engage guide body 25, which is in a groove 26 of the Sleeve 3 are axially immovable, but are arranged to be movable tangentially. In the area of the annular groove 12 has the Sleeve 3 has a transverse bore 27 in which a ball 28 is guided, which acts on a plunger 28 'The plunger 28 'is guided tightly in a bore 29 in the housing 1 and then penetrates a space 30 larger Diameter and a flow cross section 31, which is surrounded at its end by a valve seat 32 A Closing body 33 is used to hermetically seal Closing the valve seat 32 and is of a Closing spring 34 loaded, which is located together with the closing body 33 in a space 35, which by a plug 36 is closed to the outside. The plug 36 also serves as an abutment for the Closing spring 34. A manually operated 3/3-way valve 37 has three switching positions 0, a and b and three connections P, A and T. The connection P is connected to a pressure medium source 38, the connection T with

a storage container and the connection A with a channel 39 in the housing 1, which opens into the space 30. Another channel 40 branches off from the space 35 and is connected to a working space 41 of a single-acting piston-cylinder system 42 A piston dipping into the cylinder 43 has the reference number 44. Tension springs 45 between piston 44 and cylinder 43 serve as the external restoring force. A channel 46 branches off from space 30 and opens into bore 7 in the area of annular groove 12. A bore 47 inside of the Entsperrkobelns 8 leads to its free end face 48, which serves as an active surface

To explain the mode of operation, the states shown in FIGS. 1 and 2 are assumed. The piston 44 is extended and the 3/3-way valve is in its switch position »0 <c. Port A is depressurized. The ball 28 is located in the area of the annular groove 12 so that the plunger 28 'has no contact with the closing body 33. This is therefore pressed by the closing spring 34 and the pressure in the system 41, 40 and 35 on the valve seat 32 so that the Syr .tem 4i, 40 and 35 is hermetically sealed. The guide body 25 is located on the notch 17 ', whereby the stroke limitation at this point does not necessarily have to be done by the notch 17', but also by striking the end face 48 on the plug 5 from the outside can be. It is important, however, that the guide body 25 is actually located within the straight-line guide 17. If the piston 44 is now to be brought to retract, the 3/3-way valve 37 is switched to switch position "a". This activates system A, 39,30 , 31,46,12,47,48 put under pressure As a result, once the closing body 33 is lifted from its seat and, on the other hand, the release piston 8 is displaced against the force of the return spring 9 by the application of pressure to its active surface 48. The cone 13 comes into contact with the ball 28, which slides or rolls up the cone 13 until it rests on the shoulder 14. The plunger 28 'now has contact with the closing body 33 and holds it in the open position. With the stroke of the unlocking piston 8, the guide body 25 has passed through the straight guide 17 and at the end 17 ″ of the inclined guide 21, after which it is in the straight guide 18 to the stroke limit 18 ', which can also be replaced by an external stop. has come It does not matter whether the guide body 25 has thereby moved in the groove 26, or whether the release piston 8 has undergone a rotation. the 3/3-Wegeveniil 37 is now switched to its switch position "6", whereby the compound a - T is established and all spaces and channels previously pressurized are depressurized. The expression "depressurized" - is to be understood here in such a way that certain static pressures are not taken into account Oils return spring therefore pushes the release piston again in the opposite direction. The guide body 25 moves from the stroke limiter 18 'over the straight guide g 18 up to its end 18 ″, reaches the straight guide 19 via the inclined guide 22 and engages at its end 19 ′. This notch results in the figure shown in FIG. 2 switching position shown. It is important that the ball 28 still rests on the shoulder 14 so that the closing body 33 remains unlocked via the ball 28 and the plunger 28 '. The piston 44 can

ίο therefore retract completely. If the piston 44 is to be extended again, the 3/3-way valve 37 is switched to the switch position "a" again, so that all rooms and channels are again connected to the pressure medium source 38 via the connection PA. The release piston 8 is pushed further against the force of the return spring 9 by the pressure on its active surface 48. The ball 28 continues to have contact with the shoulder 14. The guide body 25 moves in the straight guide 19 and arrives at its end 19 ″ in the inclined guide 23 and from there into the straight guide 20 to the stroke limiter 20 ', the stroke limiter also could be effected here by striking the unlocking piston 8 on the plug 6.

The piston 44 extends as a result of pressure in the working chamber 41. This extension is ended when the 3/3-way valve 37 is switched to its switching position b . The system 39,30,31,46,12,47,48 is depressurized so that the return spring 9 pushes the unlocking piston 8 back. The guide body 25 passes through the straight guide 20 to position 20 "and from there via the inclined guide 24 into the straight guide 17 and there up to the detent 17 '. The first switching position is thus reached again and the ball 28 is again in the area of the annular groove 12. The closing body 33 is no longer unlocked and sits tightly on the valve seat 32. Working space 41, channel 40 and space 35 are tightly sealed. When the pressure is applied again, the cycle will be repeated. To unlock or lock, the sequence switch position "a" - switch position "Zx" or, in other words, the sequence "pressure load - pressure relief" is necessary It is clear that this can be done from a distant point and, instead of the manually operated 3/3-way valve, some other type of switchover oil valve can be used. Of course, the unlocking piston can also be arranged coaxially to the unlocking direction of the lock body, so that it could unlock without the interposition of transmission elements. Only one example was given for the interchangeable locking device! specified. Further basic possibilities are familiar from the generally known ball lock catches. Finally, it is also conceivable to carry out rotary steps for the unlocking pin

ι) leave and alternate his coat with erivabenen and to equip deep places that have a pestle make different strokes.

For this 2 blue. drawings

Claims (1)

Claim: Easily releasable check valve in seat valve design a) with one that can be acted upon by a control pressure against a restoring force a closing body in the opening direction directly or with the interposition of a plunger acting unlocking piston b) with a switching position and corresponding to a closing body tightly seated on its valve seat c) a second closing body corresponding to one lifted off the valve seat Switch position, characterized in that d) the unlocking piston (8) is provided with a known interchangeable locking device, which alternate in the direction of movement caused by the restoring force entests · holds in the first or second switch position, and e) the control pressure is always the pressure acting on the closing body (33) in the opening direction serves